Skin and integument Flashcards
1
Q
Skin microstructure: Epidermis
- Structure
- Layers
A
- Stratified squamous epithelium containing keratinocytes and melanocytes
- 4 to 5 layers
2
Q
Skin microstructure: Dermis
- Structure (3)
A
- Connective tissue matrix of collagen and elastin
- Contains a large network of blood vessels, nerve endings and lymphatics
- Also contains immune cells (e.g. macrophages)
3
Q
Skin microstructure: dermis
- Layers (2)
A
- Papillary layer: interdigitates with epidermis
- Reticular layer: contains sweat / sebaceous glands and hair follicles
4
Q
Subcutaneous layer (hypodermis):
- Structure
- Roles
A
- Areolar connective tissue and adipose
- Acts as energy store, shock absorption, insulator and allows movement
5
Q
Scalp:
- Structure
- Amount of layers
A
- Skin (thin) and subcutaneous tissue overlying the skull (neurocranium)
- 5 layers
6
Q
Scalp structure:
S.C.A.L.P
A
S-skin
C-connective tissue
A-aponeurotic layer
L-loose connective tissue
P-pericranium
7
Q
Scalp wounds: can be alarming
P
S
B
A
P
A
- Profuse bleeding - good vascular supply
- Swelling - blood can expand the loose connective tissue layers
- Bruising
- Aponeurosis appears white (“down to the bone”)
- Potential for brain injury
8
Q
Skin ligaments:
- Structure
- Role
- Determines
A
- Numerous small fibrous bands
- Attach dermis to underlying deep fascia
- Length and density determines skin mobility
9
Q
Rash: definition
A
- A change of the human skin which affects its colour, appearance, or texture (internal or external)
10
Q
Rash and colour change:
- Red
- Blue
- Yellow
A
- Red: blushing, heat distribution, insect bite infection
- Blue: cyanosis
- Yellow: jaundice indicative of bilirubin breakdown
11
Q
The skin as a physical barrier: (2)
A
- Protects internal organs from wear and tear and damage
- Prevents transepidermal water loss due to the hydrophobic nature of keratin and lipids
12
Q
The microbiome barrier: (2)
A
- A living first response barrier that transmits signals about potential pathogens to the immune system in the skin
- shapes regulatory immune response and development of tolerance
13
Q
The immune barrier: epidermis
- K
- L
A
- Keratinocytes and resident immune cells in epidermis defend against potential pathogens
- Langerhans cells - antigen presenting cells activate T cells forming adaptive immune responses
14
Q
The immune barrier: Dermis (6)
A
- Mast cells
- macrophages
- dendritic cells
- B and T cells
- NK cells
- plasma cells
15
Q
Chemical barrier: Skin pH
- Explanation
A
- Skin has an acidic pH, maintained by the acidity of sweat and conversion of triglycerides to fatty acids
16
Q
Chemical barrier: skin pH
- Effect on microbial barrier function (2)
A
- Acidic pH inhibits pathogen growth including S. aureus
- An increase in pH from 5.5 to 6.5 decreases the efficacy of antimicrobial peptide dermcidin by 40%
17
Q
Chemical barrier: skin pH
- effects on transepidermal water loss (2)
A
- Lipids that control transepidermal water loss are produced by enzymes that require an acidic pH
- Neutralizing acidic pH decreases physical barrier properties of epidermis
18
Q
Vitamin D: effects on skin (6)
- D&P
- A-M E
- S
- P
- A
- H
A
- Differentiation and proliferation
- Anti-microbial effects
- Sebaceous gland regulation
- Photo-protection
- Adaptive immunity
- Hair follicle cycling
19
Q
Rapidly adapting receptors:
- Role
- Examples (3)
A
- Detect vibrations, providing timing information over stimulus intensity
1. Pacinian corpuscles
2. Meissner’s corpuscles
3. Hair follicle afferents
20
Q
Receptive field sizes of different receptor types:
- Superficial receptors
- Deep receptors
A
- Superficial receptors: small receptive fields and sense fine details and textures
- Deep receptors: larger receptive field sizes
21
Q
Receptor types:
- Rapidly adapting
- Slowly adapting
A
- RA: an initial response that decays rapidly, good for timing but not intensity
- SA: prolonged response, good for information on stimulus intensity
22
Q
Spacial acuity: (2)
A
- ‘Two point discrimination’, varies across the bodies surface in relation to peripheral innervation density
- The face and lips have the best spacial acuity as they have the highest density of receptors
23
Q
Experience dependant plasticity of cortical maps: (2)
A
- Maps are not fixed but change with sensory experience or peripheral damage
- This plasticity allows a degree of functional recovery from intracerebrovascular accidents (e.g. stroke)
24
Q
Disorders of tactile sensation: Paresthesia
A
- Burning or prickling sensation, often accompanied by numbness, usually painless and felt in the hands and feet
25
Paresthesia: transient causes (4)
- pressure-induced, hyperventilation, viral infection, reactive hyperaemia
26
Paresthesia: chronic causes (5)
- Vascular disorders, metabolic disorders (diabetes), malnutrition, neuropathy, arthritis
27
Disorders of tactile sensation: tactile hyperesthesia
- Definition
- Example
- Increased tactile sensitivity due to peripheral neurological disorders, but may have central basis, such as sensory defensiveness in ASD
- e.g. herpes zoster virus, peripheral neuropathy
28
Disorders of tactile sensation: tactile hypoesthesia
- Definition
- Example (3)
- Numbness, reduced tactile sensitivity, predominantly due to damage of afferent nerves
- e.g. ischemia due to vascular disorders, decompression sickness, thiamine deficiency
29
Cutaneous pain sensation:
- Free nerve endings in skin mediate pain sensation and their properties depend on the channels they express
30
Pain receptor types (3)
- Polymodal nociceptors
- Mechano-cold nociceptors
- Mechanically insensitive nociceptors
31
- Polymodal nociceptors:
mechanical, thermal and chemical stimuli
32
- Mechano-cold nociceptors: mechanical and cold stimuli
mechanical and cold stimuli
33
Mechanically insensitive nociceptors: chemical and thermal stimuli
chemical and thermal stimuli
34
Hyperalgesia:
Allodynia:
- Hyperalgesia: an excessive response to noxious stimuli
- Allodynia: the production of pain by non-noxious stimulant
35
Axon reflex to pain stimuli: (3)
- Nociceptor activity causes the release of substance P from axon collaterals
- This increases blood flow and releases inflammatory agents (histamine) causing redness, swelling and heating
- Contributes to sensitization of nociceptors and primary hyperalgesia
36
Primary hyperalgesia (A, B and D) (2)
- Chemically mediated sensitisation of nociceptors results in increased firing rate
- Sensitising agents include bradykinin, prostaglandins, cytokines
37
Secondary hyperalgesia (C)
- Occurs without an increase in the firing rate of nociceptors - increased responsiveness of central pain circuits
38
Allodynia:
- Sensitisation and reorganisation of tactile input to central pain pathways and possibly changes to their descending modulation
39
Atopic dermatitis (eczema)
- Statistics (3)
- Wider effects
- Affects 1 in 10 people
- 25% of children
- 90% develops before the age of 5
- Huge burden on economy and loss of productivity for patients and caregivers
40
Acne:
- Affects 85% of 12-24 year olds
- Most common skin condition in the UK
- Multiple different types
41
Psoriasis:
- 2% of the Uk population
- Multiple different types, associated comorbidities
- CVS disease, DVT/PE associated
42
Rosacea:
- 2.5-5% of the population
- Reddening around the facial area
43
Skin cancer: ABCDE
A - Asymmetry
B - irregular Border
C - Colour alterations
D - Diameter > 6mm
E - Evolving
44
Atopic eczema and mental health:
- Pruritus severity increased by depression, depression may decrease the itch threshold
45
Psoriasis and worry:
- 40% of patients associated onset/exacerbation of their psoriasis to "times of worry"
- 40% exceed pathological worry levels on the PSWQ
46
Acne causing mental health issues: (4)
- Depression
- Anxiety
- OCD
- Suicidal ideation (5.6%)
47
Trichotillomania:
- Definition
- Adults vs kids
- Scale
- A condition where people cannot resist an urge to pull out their hair
- Adults, common psychiatric co-morbidities
- Children, habit
- Small areas to total alopecia
48
Delusional parasitosis:
- Monosymptomatic psychosis
- Victims acquire a strong delusional belief that they are infested with parasites
49
Morgellon's disease
- A woman could see coloured fibres on her sons skin
- Delusional parasitosis via proxy
50
Dermatitis Artefacta:
- Intentional, self-inflicted skin disease (self harm)
- Hard to diagnose, more common in healthcare workers
51
Body dysmorphic disorders: (3)
- Phobic disorder of body appearance
- 1-2% of the population
- Linked to depression, social isolation and 80% experience suicidal ideation
52
Homeotherms:
- Physiological mechanisms to regulate temperature
53
Poikilotherms:
- Temperature varies with that of external environment
54
Core and shell body temperatures:
- Core: key areas around vital organs - very little temperature variation
- Shell: temperature can vary more, as a result of regulatory responses to preserve core temperature
55
Sites for clinical measurement of core temperature:
R
S
A
F
EAM
- Rectal
- Sublingual
- Axillary
- Forehead
- External auditory meatus
56
Mechanisms of body temperature:
- Heat production
- Heat loss
- Production: metabolism = 100%
- Loss:
Evaporation = 20%
Radiation = 40%
Convection = 40%
57
Thermoreceptors: characterised by (4)
- Specificity
- Sensitive to dynamic as well as absolute changes
- Small receptive fields
- More cold than warm peripherally
58
Thermoreceptors: central controller (2)
- Set point is generated at the posterior hypothalamus
- Main transmitters are Ach and prostaglandins
59
Hyperthermia: heat exhaustion
1. Definition
2. Causes
1. Prolonged exposure to raised environmental temperature
2. Strenuous activity, dehydration, alcohol use, overdressing
60
Hyperthermia: heat exhaustion
3. Symptoms
4. Treatment
3. Faintness, dizziness, fatigue, increased HR, decreased BP, cramps, nausea, headache
4. Stop activity and rest, move to cooler place, rehydrate
61
Hyperthermia: heat stroke
1. Defintion
2. Risks
1. Definition: Failure to regulate core temperature (40oC or more)
2. Risks: Can lead to organ damage
3. Symptoms: Heat exhaustion ++ (racing HR, hot skin, confusion, agitation)
62
Hyperthermia: heat stroke
4. Causes
5. Treatment
4. Can be exertional or environmental
5. Ice packs / cooling blankets, iv fluids, support injured organs
63
Malignant hyperthermia:
- Aberrant response to Halothane gas
- Aberrant cellular Ca handling leads to increased muscle metabolic rate, leading to heat generation
- Must be treated immediately
64
Hyperhidrosis: excessive sweating
- Prevalence
- Location
- Onset
- occurs in 2-3% of people (US)
- Axillary and/or palmoplantar, sometimes face
- Adolescence onwards
65
Hyperhidrosis:
- Primary
- Secondary
- Idiopathic
- hyperthyroidism, some medications, diabetes, obesity
66
Hyperhidrosis treatments: (4)
- Aluminium (chloride hexahydrate) containing antiperspirants (blocks sweat glands)
- Anticholinergics
- Botox
- Surgery
67
Acclimatisation: heat adaptation (4)
1. Lowering of sweat threshold
2. Shift of threshold for shivering to a lower temperature
3. Thyroid hormones
4. Behavioural changes
68
Acclimatisation: cold adaptation (4)
1. Increase in functional insulation ( skin blood flow)
2. Shift of threshold for shivering to a lower temperature
3. Thyroid hormones
4. Behavioural changes
69
Scarring: (2)
- A consequence of wound fibroblasts depositing misaligned and too much cross-linked collagen at the healing wound site
- Triggered by inflammation at the wound site
70
Identifying skin lesions: flat
- Macule
- Patch
- Macule < 0.5cm
- Patch > 0.5cm
71
Identifying skin lesions: raised
- Papule
- Nodule
- Plaque
- Papule: raised, solid lesion, <1cm
- Nodule: Raised, solid lesion, >1cm
- Plaque: Large, plateau, superficial
72
Seborrhoeic keratosis:
- Highly variable appearance, flat or raised papule or plaque, colour variation
- Smooth, waxy or warty surface
73
Basal cell carcinoma:
- Structure
- Location
- Prevalence
- Prognosis
- Slow growing lesions, classically a nodule with a central crust
- Tumour of the basaloid epithelium, commonly caused by sun exposure
- More common in men, 50% will develop another BCC in 3 years
- Does not increase mortality, very rarely metastasize
74
Keratin horn:
- Problem
- Solution
- The horn prevents a diagnosis for the underlying lesion
- 50% benign base, given risk of malignancy it should be referred to secondary care
75
Squamous cell carcinoma:
- Type
- Prognosis
- Risks
- Prevalence
- Keratinocyte tumour
- Larger lesion = worse prognosis
- Metastasize locally to lymph nodes
- More common in elderly males, 50% develop another in 5 years
76
Keratocanthoma:
- Features
- Location
- Timespan
- Treatment
- Rapidly growing volcanic like lesion
- Can form on sites of trauma, related to hair follicles
- Resolve spontaneously
- Not malignant but very similar to SCC, smart to treat it as such until proven otherwise
77
Actinic keratosis:
- Location / prevalence
- Risk
- Options
- Common - often on protruding bits and mens scalps
- Pre-cancerous, rare to progress to SCC but risk increases with amount
- Multiple treatment options, prevention is better than cure
78
Sebaceous cyst:
- Type
- Treatment
- Benign lesions
- Surgical lesions when not inflamed. Make sure the entire sac is removed or will reoccur
79
Lipoma:
- Characteristics (3)
- Benign fatty lumps
- Mobile under skin
- Can be painful if traumatised
80
Dermatofibroma:
- Type
- Cause? (2)
- Benign fibrous nodules
- Probably due to a reactive process
- If multiple, consider an altered immune state
81
Cherry angiomas: (3)
- Red spots, slightly raised
- Can be linked to pregnancy and rarely malignant
- Bleed a lot if punctured
82
Erythema Multiform:
- Appearance
- Causes (2)
- Resolution
- Multiple red spots
- Commonly caused by HSV infection
- Less than 10% caused by drugs
- Spontaneously resolve within 4 weeks, may be recurrent
83
Cellulitis and Erysipelas:
Shared factors
- Common factors
- Unilateral, hot, tender leg, blisters
84
Cellulitis and Erysipelas:
Shared factors
- Risk factors (5)
- Defective barriers
- Diabetes or immunosuppression
- Chronic lymphoedema
- Peripheral vascular disease
- Previous cellulitis
85
Cellulitis and Erysipelas:
- difference
- Cellulitis: deep
- Erysipelas: superficial
86
Lipodermatosclerosis:
- Definition
- Symptoms
- Treatment
- Chronic panniculitis (fat inflammation)
- Acute phase may be painful and red, no systemic upset
- treated by topical steroid and emollients
87
Paronchyia:
- Causes: acute and chronic
- Acute treatment (3)
- Acute, usually bacterial
- Chronic, may be fungal
Acute treatment:
- Warm soaks
- Topical antiseptic if localised
- I + D, dressing, packing
88
Erythroderma: general info (3)
- Generalised, blanchable redness of skin
- Caused by increased blood flow
- >90% of body surface area
89
Erythroderma: Causes
Der
P
D
C or L
I
- Dermatitis 15-40%
- Psoriasis 8-25%
- Drugs 10-28%
- CTCL or leukaemia 15%
- Idiopathic 30%
90
Erythroderma: signs (5)
P
S
K
N
L
- Pustules
- Superficial blisters
- Keratoderma
- Nail changes
- Lymphadenopathy
91
Erythroderma: treatment (4)
- Stop all non-essential drugs
- Emollients
- Treat underlying infections
- Fluid balance / temperature control
92
Pyoderma gangrenosum:
- Neutrophilic dermatosis
- Acutely painful, rapidly growing ulcers
- 50% caused by underlying systemic disease
93
Necrotising fascitis
- Description
- Prevalence
- Location / effects
- Bacterial infection of soft tissue and fascia
- 50% occur in young healthy individuals
- Common on lower leg, severe pain and systemically unwell
94
Steven Johnson Syndrome (SJS):
- Descriptions (2)
- Prognosis
- Life threatening drug reaction
- Epidermal necrosis
- High mortality rate
95
Toxic Epidermal Necrolysis (TEN):
- Life threatening drug reaction
- Skin falls off at literal touch
- >60% mortality rate, real bad shit
96
Eczema herpeticum:
- Description
- Cause
- Treatment
- Small, punched out ulcers
- Herpes simplex type 1 and 2
- Can become a dermatological emergency, if widespread admit for IV acyclovir
97
Generalised pustular psoriasis:
- Sterile pustules on an erythematous background
- Stopping steroids, pregnancy, drugs, infection
- Can be de novo
- RARE
98
Staphlococcal scalded skin syndrome:
- Description
- Prevalence
- Treatment
- Localised staph infection that releases endotoxins, leads to cleaving of the epidermis
- More common in children and infants but can occur at any age
- Monitor for infection and take swabs, good prognosis
99
Sun, vitamin D and skin of colour:
- Skin cancer
- Nitrous oxide
- Less risk of skin cancer but caught later if it occurs
- Sunlight produces nitrous oxide in the skin, leading to health benefits. More exposure needed for people of colour
100
Mongolian blue spot:
- Description
- Location
- Cause
- Duration
- Lumbosacral dermal melanocytosis
- May be diffuse or just one patch
- Caused by the entrapment of melanocytes in the dermis of developing embryos
- Usually subsides by age 4
101
Ochranosis: (2)
- From hydroquinone deposition in the skin, skin lightening products
- No treatment, darkens skin
102
Hypopigmentation secondary to corticosteroid injection:
- Often permanent
- More common in subcutaneous or intradermal injections
103
Vitiligo:
- Acquired depigmentation syndrome
- Autoimmune condition
- 1-8% of population, 80% occurs before the age of 30
104
Dermatosis papulosa nigra:
- Type
- Appearance
- Benign
- Multiple smooth papules on the face and neck
105
Melanonycia: (3)
- Dark lines through the nail bed
- Benign
- Look for multiple lines
106
Acral melanoma:
- Common in darker skin, 29-72% of melanomas in skin of colour are acral
- 1-3% of total melanomas are acral
- Not related to sun exposure
107
Subungual melanoma: (2)
- Not related to sun exposure, may be trauma related
- Most common melanoma in the darkest skin types
108
Integument: epidermal derivatives (3)
- Follicular structures (hair)
- Glandular structures (sebaceous and sweat glands)
-Keratinous structures (nails)
109
Layers of epidermis surface epithelium: (4)
K
G
P
B
- Keratinised layer
- Granular cell layer
- Prickle cell layer
- Basal (germinal) keratinocyte layer
110
Normal epidermal cell types: non-epithelial (3)
- Melanocytes
- Langerhan's (dendritic) cells: type of macrophage
- Merkel cells: sensory receptors to touch
111
Melanocytes:
- Location
- Role
- Located and attached to basal epidermis
- Melanin synthesis from tyrosine occurs in melanosomes. It is then transported to kerantinocytes by the melanocyte by endocytosis of dendritic tips
112
Dermis: specialisations (4)
- Superficial
- Deep
- Contains
- Variations
- Superficially contains loosely arranged collagen, elastic fibres, fibroblasts (papillary layer)
- Deeper layer contains more densely arranged collagen, elastic fibres (reticular layer)
- Contains small neurovasculature and lymphatics and receptors
- Thickness varies depending on site (thin on eyelids, thick on soles)
113
Hypodermis:
- Structure
- Roles (3)
- Variable thickness and composition; predominantly composed of areolar connective tissue and loose adipose tissue
- Insulation, energy storage and shock absorption
114
Sebaceous glands: development
- Develop as an outgrowth of the hair ecternal root sheath
115
Sebaceous glands: holocrine glands
- Secretion (sebum) formed from disintegrated cells and discharges onto hair shaft
- Sebum is oily and coats the hair and skin surface (moisture and waterproofing)
116
Sebaceous glands: tarsal glands
- Enlarged sebaceous glands which open on the eyelid margin
117
Eccrine sweat glands:
- Location
- Structure
- Secretes??
- Role
- Located all over the body
- Simple secretory coil in dermis with pore opening on surface via duct
- Secretes watery, hypotonic fluid, pH 4-6
- Thermoregulation and lubrication
118
Apocrine sweat glands:
- Structure
- Substance
- Role
- Location
- Straight narrow ducts running parallel to hair follicles
- Thick secretion into adjacent hair follicle
- Lubrication and sweat, under hormonal control
- Found in specific regions (axilla, areola of nipple, groin)
119
Healing by primary intention: (2)
- Wound edges are approximated by sutures, staples or glue
- Complete return to function, minimal scarring and loss of appendages
120
Healing by secondary intention: (2)
- The wound is left open and required to heal from the bottom up via granulation
- Wider, more visible scarring
121
Pathogenesis of atopic dermatitis:
1. Abnormal production ....
a)
b)
1. Abnormal production of skin barrier protein such as filaggrin production
a) Increase transepidermal water loss
b) Skin dryness and itching
122
Pathogenesis of atopic dermatitis:
2. Abnormalities of ...
a)
b)
2. Abnormalities of the immune system
a) Overproduction of IgE to allergens e.g. foods, mites
b) Decrease production of antimicrobial protein for killing bacteria
123
Pathogenesis of atopic dermatitis:
3. E
a)
b)
3. Environmental exposures
a) specific factors e.g. allergens, S aureus
b) Nonspecific factors: irritants, extreme temperatures, stress, sweating
124
Emollients:
- moisturising treatments applied directly to the skin
- Hundreds of them available, with varying formularies
125
Emollient types: lotions
- Thin, good for damaged skin and hairy areas. Easy to spread but not very moisturising
126
Emollient types: Creams
- Not very greasy, middle ground moisturising, good for day time use
127
Emollient types: ointments
- Thick, greasy, very moisturising, good for very dry skin and night time use
128
Intertrigo:
- Description
- Cause
- Treatment
- Common inflammatory skin condition
- Caused by skin on skin friction, intensified by heat/moisture
- Combination treatment of steroid, antifungal and antibacterial (trimovate). Keep area dry
129
Rosacea:
- Description (2)
- Combination of papules and pustules
- Ocular involvement is common
130
Rosacea: treatment
- Flushing
- Papules, pustules and nodules
- Vasoconstrictors
- Metronidazole gel, oral tetracyclines, topical ivermectin
131
Management of plaque psoriasis:
E
M
C & B
L
S
- Emollients
- Mild topical steroids
- Calciptriol and bethamethasone
- Light therapy
- Systemic agents
